steve harrigan is live at cape canaveral. >> a solemn day at the complex. a sense of remembering and sense of gratitude for those that gave their life in space exploration. three of the major tragedies in nasa occurring in different years but on in the same week beginning in 1967 with apollo one a fire claim the lives of three astronauts including gus grissom. then in 1986 the space shuttle challenger exploding after 73 seconds in flight. of course on board the challenger was the first teacher in space. it was later found that a faulty seal around a booster rocket was responsible for that crash. finally ten years ago today, this time it was the space shuttle columbia after a selling 16-day mission. that orbiter coming apart minutes away from home. some of the family members of the seven crew members here today to mark that with remembrance and gratitude trying to push the envelope. back to you. >> alisyn: i remember that day vividly. >> 20 years after her kidnapping made worldwide headlines, a hostage survivor opens up about that traumatic experience. she c